The Share button for AddThis, and similar social aggregators, is NOT the same as the old FB Share button.

Those Share buttons, indeed, have very little to do with Facebook. Instead, they provide access to multiple social plugins, i.e., typically those much smaller than Facebook, Twitter, et al, those too small or insignificant to rate their own buttons.

If your question is whether you should use AddThis's FB button or AddThis's Share button, I would suggest using both. They serve different purposes.

If your question is whether you should (or can) use Facebook's Share button, here is FB's own wordy answer to your question.

I wanted to ask a quick question, sorry if I'm hijacking your thread but I think it's related. Does anyone know if it's 'better' (and if so, why) to try and promote the facebook page we created for our business (i.e. and have a link to our facebook page on our website so that people can easily visit our facebook page and like us/get updates via facebook), or just have a facebook like button on our website so people can like individual pages of our site?

Sorry if this is a dumb question as I'm still learning how to use facebook...

It's actually best to do both. Your Facebook page can be used to further communicate and offer special things to your target audience. But it's also good to have them spread around any great content you have via Facebook Likes.